1. Field of the Invention
The present invention relates to cucurbit [n] uril compounds and methods of making and using the same.
2. Description of the Background
Members of the plant family cucurbitaceae exist in a variety of sizes, shapes and colors. Prime examples include pumpkins, squash, zucchini, cucumbers, cantaloupe, and gourds. The similarity between the molecular shape of the hexameric compound cucurbit [n] uril, i.e. CB[6], and the shape of a pumpkin lead Mock and co-workers to name this compound cucurbituril. In addition to being pumpkin-shaped, the compound CB[6] has two carbonyl-lined portals and a hydrophobic cavity. Through their pioneering work, the groups of Mock and Kim have defined the molecular recognition properties of CB[6] and demonstrated its application in self-assembly studies. Recently, the cucurbituril family gained four new members—CB[5], CB[7], CB[8], and CB[5] @ CB[10] that differ in molecular size from CB[6].

CB [5] (diameter: 4.4 Å, volume 82 Å3), CB [6] (diameter: 5.8 Å, volume 164 Å3), CB [7] (diameter: 7.3 Å, volume 279 Å3), and CB [8] (diameter: 8.8 Å, volume 479 Å3) have diameters and cavity volumes that are similar to those of α-, β- and γ-cyclodextrin which suggests their potential broad utility. More over, these compounds have been shown to be amenable to derivatization reactions after formation as recently demonstrated by Kim and co-workers. JACS 2003, 125, 10186-10187.
The preparation of cucurbituril compounds using functionalized glycoluril monomers in CB[n]-forming reactions began shortly after one of Mock's pioneering papers, and resulted in the synthesis of Me10 CB[5], Cy5 CB[5], Cy6 CB[6], Ph2 CB[1,5], and Me6 CB[3,3]. For a review of cucurbit [n] uril homologues and derivatives, see Lee, W. et al. Acc. Chem. Res. 2003, 36, 621-630.
Despite this relative success, no general approach to the synthesis of CB[n] compounds with control over size and functionalization pattern has been reported. Further, currently available CB[n] compounds made by existing synthetic methodologies exhibit poor solubility characteristics and are purified with difficulty. Thus, a need exists for a different approach to the synthesis of CB[n] compounds, which affords control over size and functionalization pattern, as well as improved product solubility and greater ease of purification. Ease of purification is important in as much as current synthetic methodologies for preparing CB[n] compounds are unselective and result in a mixture of CB[n] products requiring separation and purification.